Cylindrical roller bearing

ABSTRACT

A cylindrical roller bearing includes a flanged outer race having two inwardly extending flanges. One of the flanges is a flange ring separate from the outer race and fixed to the outer race. Cylindrical rollers are mounted between the outer race and a flangeless inner race, and retained by a retainer which are located radially inwardly of the pitch circle of the cylindrical rollers. With this arrangement, it is not necessary to reduce the widths of pillars of the retainer even if the load capacity is increased by increasing the size or the number of the cylindrical rollers, so that it is possible to increase the load capacity while ensuring strength of the retainer. Also, even if the inner race is separated from the bearing, it is possible to prevent separation of the cylindrical rollers as well as the retainer, which retains the cylindrical rollers, from the outer race.

TECHNICAL FIELD

The present invention relates to a cylindrical roller bearing used underlarge radial loads.

BACKGROUND ART

A wind power generator system includes a speed increasing gear forincreasing the speed of a rotary shaft connected to the rotor of thewindmill to drive the generator. Since relatively large radial loadstend to be applied to the torque transmission mechanism of such a windpower generator system, the rotary shaft and the torque transmissionshaft in the speed increasing gear are rotatably supported bycylindrical roller bearings which are large in load capacity.

Today, it is increasingly required that cylindrical roller bearings havea long life when used under further heavier loads. This requirement isfulfilled by increasing the size of the cylindrical rollers, orincreasing the number of the cylindrical rollers. However, either of theabove solutions narrows the distances between the adjacent cylindricalrollers on the pitch circle of the cylindrical rollers. This makes itnecessary to reduce the widths of the pillars of the retainer, which inturn raises a concern regarding the strength of the retainer.

A full type cylindrical roller bearing, i.e. a bearing having noretainer, which is disclosed in JP Patent Publication 9-88970A, is largein load capacity and is suitable for use under heavy loads. However,since this type of bearing has no retainer, its rotation properties arenot good, and also, damage to the surfaces of the cylindrical rollers isconcerned because the cylindrical rollers contact each other whilerotating.

JP Patent Publication 2008-03893A discloses a cylindrical roller bearingof which the pillars of the retainer is located radially inwardly orradially outwardly of the pitch circle of the cylindrical rollers. Bylocating the pillars of the retainer offset from the pitch circle of thecylindrical rollers. As a result, it is possible to increase the size ofthe cylindrical rollers or increase the number of the cylindricalrollers, which in turn makes it possible to increase the load capacityof the cylindrical roller bearing while maintaining good rotationproperties.

The cylindrical roller bearing disclosed in JP Patent Publication2008-03893A includes a bearing race having two flanges, and a bearingrace having one flange. Since the retainer is disposed between thesebearing races so as to be offset from the pitch circle of thecylindrical rollers toward the bearing race with two flanges, if thebearing race with a single flange is separated from the bearing, thecylindrical rollers are also separated such that the bearing becomescompletely disassembled. Thus, it is extremely troublesome to assemblethis cylindrical roller bearing.

In order to prevent separation of the bearing race with a single flange,it is necessary to mount a snap ring at the end of a cylindrical racewayof the bearing race with a single flange. However, since a snap ring isinsufficient in strength, it is difficult to guide the end surfaces ofthe rollers with a snap ring.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a cylindrical rollerbearing which is large in load capacity, while keeping sufficientstrength of the retainer, and which can be assembled easily and also canbe easily mounted to another member.

In order to achieve this object, the present invention provides acylindrical roller bearing comprising an outer race formed with acylindrical raceway on an inner periphery of the outer bearing race, aninner race formed with a cylindrical raceway on an outer periphery ofthe inner race, a plurality of cylindrical rollers disposed between theinner race and the outer race, and a cylindrical retainer formed withcircumferentially spaced apart pockets which are equal in number to thecylindrical rollers and in which the respective cylindrical rollers arerotatably received. A first one of the outer race and the inner race isa flanged bearing race having a first flange configured to guide firstend surfaces of the respective cylindrical rollers, and a second flangeconfigured to guide second end surfaces of the respective cylindricalrollers, and a second one of the outer race and the inner race is aflangeless bearing race having no flanges. The retainer includes pillarsdefined between the respective adjacent pairs of the pockets and locatedbetween the pitch circle of the cylindrical rollers and the raceway ofthe flangeless bearing race. At least one of the first and secondflanges comprises a flange ring which is a separate member from, andfixed to, the flanged bearing race, and the flange ring is fixed to theflanged bearing race after fitting the cylindrical rollers in theflanged bearing race.

In this cylindrical roller bearing, by fitting the retainer, with thecylindrical rollers fitted in the pockets of the retainer, to theflanged bearing race, to which the flange ring is not yet mounted, andthen by fixing the flange ring, the cylindrical rollers and the retainerare inseparably held by the flanged bearing race. In this state, bymounting the flangeless bearing race, the cylindrical roller bearing isassembled.

The cylindrical roller bearing can thus be easily assembled. Once thebearing is assembled, even if the flangeless bearing is separated, theflanged bearing race, the retainer, and the cylindrical rollers remainassembled and inseparable. This subassembly can thus be easily mountedto a shaft or a housing.

Since the pillars of the retainer, which are defined between theadjacent pockets of the retainer, are located between the pitch circleof the cylindrical rollers and the cylindrical raceway of the flangelessbearing race, it is possible to increase the size or the number of thecylindrical rollers while maintaining sufficient strength of the pillarsof the retainer. It is therefore possible to increase the load capacityof the cylindrical roller bearing while maintaining sufficient strengthof the retainer.

By locating the pillars of the retainer radially offset from the pitchcircle of the cylindrical rollers, radial movement of the cylindricalrollers decreases, which makes it possible to dispense with lead-inchamfers at both axial ends of the raceway of the flangeless bearingrace. By dispensing with the lead-in chamfers, it is possible toincrease the distance by which the flanged bearing race and theflangeless bearing race can move axially relative to each other.

The flange ring of the cylindrical roller bearing according to thepresent invention can be fixed to the bearing race by tightening bolts,by pins, by fitting annular fastening members in annular grooves eachformed partially in the peripheral surface of the flanged bearing raceand partially in the peripheral surface of the flange ring so as tobridge them when the flange ring is brought into abutment with the endsurface of the flanged bearing race, by welding, by bringing the flangering itself into threaded engagement with a thread formed on theperipheral surface of the flanged bearing race at one end thereof andtightening the flange ring, or by press-fitting the flange ring itselfonto the peripheral surface of the flanged bearing race at one endthereof.

If the flange ring is to be fixed in position by tightening bolts, thebolts may be inserted through axial bolt inserting holes formed in theflange ring and driven into threaded holes formed in the end surface ofthe flanged bearing race. Alternatively, means for fixing the flangeusing bolts comprises a small-diameter cylindrical surface provided atthe axial end of the flanged bearing race and formed with radial boltinserting holes, a cylindrical portion provided on the flange ring andfitted on the small-diameter cylindrical surface, the cylindricalportion being formed with radial threaded holes, and bolts, and isconfigured such that the bolts can be inserted through the boltinserting holes, and driven into the threaded holes.

If pins are used to fix the flange ring in position, the flange ring canbe fixed to the flanged bearing race by pin holes extending through theflange ring and into the flanged bearing race, and pins press-fitted inthe pin holes. Alternatively, the flange ring and bearing race can befixed by a cylindrical portion provided on the flange ring and fitted tothe end of the flanged bearing race, pin holes extending from theperipheral surface of the cylindrical portion through the cylindricalportion, and into the flanged bearing race, and pins press-fitted in thepin holes.

If the flange ring is fixed to the flanged bearing race bypress-fitting, the flanged bearing race could be radially deformed whenthe flange ring is press-fitted, and the thus deformed flanged bearingrace could make it difficult to mount the bearing to a housing or ashaft. In order to reduce such radial deformation of the flanged bearingrace, an annular groove is preferably formed in the end surface of theflanged bearing race.

By forming the retainer by pressing or from a synthetic resin, it can bemanufactured at a lower cost than when the retainer is formed bymachining.

By guiding the retainer with the cylindrical rollers, it is possible toreduce resistance to rotation of the bearing compared to when theretainer is guided by a raceway.

ADVANTAGES OF THE INVENTION

According to the present invention, since the pillars of the retainerwhich are defined between the adjacent pockets of the retainer arelocated between the pitch circle of the cylindrical rollers and thecylindrical raceway of the flangeless bearing race, it is possible toincrease the size or the number of the cylindrical rollers, and thus toincrease the load capacity of the bearing, while maintaining sufficientstrength of the pillars.

By fitting the subassembly of the retainer and the cylindrical rollersfitted in the pockets of the retainer to the flanged bearing race beforethe flange ring is mounted thereto, and then fixing the flange ring tothe flanged bearing race, the flanged bearing race, the retainer and thecylindrical rollers remain assembled, and the subassembly thereof can beeasily mounted to a shaft or a housing. Also, by mounting thissubassembly to the flangeless bearing race, it is possible to form acylindrical roller bearing. Such a cylindrical roller bearing can beeasily assembled.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially cutaway front view of a cylindrical roller bearingembodying the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG. 1.

FIG. 3 is a sectional view showing a different means for fixing a flangering.

FIG. 4 is a sectional view showing a still different means for fixingthe flange ring.

FIG. 5 is a sectional view showing a further different means for fixingthe flange ring.

FIG. 6 is a plan view of a portion where the flange ring of FIG. 5 isfixed.

FIG. 7 is a sectional view showing a still different means for fixingthe flange ring.

FIG. 8 is a sectional view showing a still different means for fixingthe flange ring.

FIG. 9 is a sectional view showing a further different means for fixingthe flange ring.

FIG. 10 is a sectional view showing a different flanged bearing racehaving two flanges.

FIG. 11 is a sectional view of a cylindrical roller bearing according toanother embodiment of the present invention.

FIG. 12 is a sectional view showing a different retainer.

FIG. 13 is a sectional view showing a still different retainer.

DETAILED DESCRIPTION OF THE INVENTION

The embodiment of the present invention is now described. As shown inFIGS. 1 and 2, the cylindrical roller bearing of the embodiment includesa flanged outer bearing race 1 (hereinafter simply referred to as “outerrace 1”) having two flanges at the respective axial ends thereof, and aflangeless inner bearing race 11 (hereinafter simply referred to as“inner race 11”). A plurality of cylindrical rollers 21 are mountedbetween the outer race 1 and the inner race 11, and retained by aretainer 31.

The outer race 1 has a cylindrical raceway 2 on the inner peripherythereof. The two flanges 3 a and 3 b extend inwardly at the respectiveaxial ends of the raceway 2, and are configured to guide the endsurfaces of the cylindrical rollers 21.

Of the two inwardly extending flanges 3 a and 3 b, the flange 3 a isintegral (one piece) with the outer race 1, while the flange 3 bcomprises a flange ring 3 b which is a separate member from the outerrace 1. The flange ring 3 b has an outer diameter equal to or slightlysmaller than the outer diameter of the outer race 1, and has an innerdiameter equal to the inner diameter of the flange 3 a. The flange ring3 b is brought into abutment with the end surface of the outer race 1,and then fixed to the outer race 1 by a fixing arrangement 40.

As shown in FIG. 2, the fixing arrangement 40 comprises axial boltinserting holes 41 formed in the flange ring 3 b and having countersunkportions, threaded holes 42 formed in the end surface of the outer race1 so as to face the respective bolt inserting holes 41, and bolts 43. Byinserting the bolts 43 through the respective bolt inserting holes 41,then driving the bolts 43 into the respective threaded holes 42, andtightening the bolts 43, the flange ring 3 b is fixed to the outer race1. If the number of bolts 43 is too few, it is difficult to stably fixthe flange ring 3 b in position. It is therefore necessary to use threeor more bolts 43, and tighten the portions of the flange ring 3 bcircumferentially equidistantly spaced apart from each other with thebolts 43.

The inner race 11 has a cylindrical raceway 12 on its outer periphery,and lead-in chamfers 13 at the respective axial ends of the raceway 12.The cylindrical rollers 21 can roll along the raceway 12 as well asalong the raceway 2 of the outer race 1.

The retainer 31 is a cylindrical member formed with pockets 32 which areequal in number to the cylindrical rollers 21 and circumferentiallyspaced apart from each other. The cylindrical rollers 21 are received inthe respective pockets 32.

The pitch circle diameter PCD of the retainer 31 is the centerlinediameter of the circular arrangement of the pillars 33 of the retainer31. The retainer 31 has an outer diameter smaller than the pitch circlediameter PCD of the cylindrical rollers 21. Thus the retainer 31 isconfigured so that pitch circle diameter of the retainer 31 is locatedbetween the pitch circle PC and the raceway 12 of the inner (flangeless)race 11. The retainer 31 includes pillars 33 defined between theadjacent pockets 32, and ring portions 34 provided at the respectivefirst and second opposed ends of the pillars 33, and is arranged suchthat the inner peripheral surfaces of the pillars 33 and the innerperipheral surfaces of the ring portions 34 are guided by the raceway 12of the inner race 11.

The retainer 31 may be formed by machining. However, since machining iscostly, the retainer 31 of the embodiment is formed by pressing metalfor reduced cost. Instead of by pressing metal, however, the retainer 31may be formed of synthetic resin.

In assembling the cylindrical roller bearing of the embodiment, thecylindrical rollers 21 are fitted in the respective pockets 32 of theretainer 31 from radially outside the retainer 31, and the subassemblyof the retainer 31 and the cylindrical rollers 21 is then fitted in theouter race 1. In this state, with the flange ring 3 b in abutment withthe end surface of the outer race 1, the bolts 43 are inserted throughthe bolt inserting holes 41 formed in the flange ring and driven intothe threaded holes 42, thereby fixing the flange ring 3 b to the outerrace 1.

With the flange ring 3 b fixed in position, the flange ring 3 b and theflange 3 a prevent axial separation of the cylindrical rollers 21 fromthe bearing, while the retainer 31 prevents separation of thecylindrical rollers 21 in the radially inward direction. Thus in thisstate, the outer race 1, the cylindrical rollers 21, and the retainer 31remain assembled together. By inserting the inner race 11 into thesubassembly of the outer race, cylindrical rollers and retainer, thecylindrical roller bearing is assembled.

As described above, by fitting the subassembly of the retainer 31 andthe cylindrical rollers 21 into the outer race 1, and then by fixing theflange ring 3 b to the outer race 1, the outer race 1, the cylindricalrollers 21 and the retainer 31 are inseparably assembled together. Thus,by inserting the inner race 11 into the subassembly of the outer race 1,cylindrical rollers and retainer, the cylindrical roller bearing can beeasily assembled. Also, since the cylindrical rollers 21 are simplyinserted into the pockets 32 of the retainer 31 and not forcibly pushedinto the pockets 32, the retainer 31 will never be deformed and thecylindrical rollers 21 will not be damaged, when assembling thecylindrical roller bearing.

Even if the inner race 11 is axially separated from the outer race 1,the retainer 31, and the cylindrical rollers 21, the latter remaininseparably assembled together, so that the latter can be easily mountedon a shaft or in a housing.

With the cylindrical roller bearing assembled as shown in FIGS. 1 and 2,since the pillars 33 of the retainer 31, which are defined between theadjacent pockets 32, are arranged inside the pitch circle PC of thecylindrical rollers 21, even if the size and/or number of thecylindrical rollers 21 is increased, the pillars 33 of the retainer 31maintain sufficient strength. In other words, with this arrangement, itis possible to increase the load capacity of the cylindrical rollerbearing while maintaining sufficient strength of the retainer 31.

In FIG. 2, in order to fix the flange ring 3 b to the outer race 1, thebolts 43 are inserted through the axial bolt inserting holes 41 formedin the flange ring 3 b, brought into threaded engagement with thethreaded holes 42 formed in the end surface of the outer race 1, andtightened. In FIG. 3, the (flanged) outer race 1 has at its axial endportion a small-diameter cylindrical surface 4 having a diameter smallerthan the outer diameter of the remaining portion of the outer race 1 andformed with radial threaded holes 45, while the flange ring 3 b has acylindrical portion 5 fitted on the small-diameter cylindrical surface 4and formed with radial bolt inserting holes 44 having countersunkportions. In order to fix the flange ring 3 b of FIG. 3 to the outerrace 1, bolts 43 are inserted through the radial bolt inserting holes44, driven into the radial threaded holes 45 formed in thesmall-diameter cylindrical surface 4, and tightened.

The fixing arrangement 40 of FIG. 3, for fixing the flange ring 3 b, isfree of the problem of separation of any of the bolts 43 in the radiallyoutward direction even if the bolt 43 loosens, because the outer race 1is ordinarily mounted in a housing. Therefore, this arrangement reliablyprevents separation of the flange ring 3 b, as well as radialdisplacement of the flange ring 3 b.

In FIGS. 2 and 3, the flange ring 3 b is fixed in position by tighteningthe bolts 43 of the fixing arrangement 40. The fixing arrangement 40 ofthe present invention is however not limited to this type. FIGS. 4 to 9show different fixing arrangement 40.

The fixing arrangement 40 shown in FIG. 4 comprises axial pin holes 46formed in the flange ring 3 b and the outer race 1, and pins 47press-fitted in the pin holes 46 to fix the flange ring 3 b in position.

A fixing arrangement as a modification of the fixing arrangement 40 ofFIG. 4 may comprise radial pin holes extending through the cylindricalportion 5 shown in FIG. 3 and into the outer race 1, and pinspress-fitted in these radial pin holes to fix the flange ring 3 b inposition.

The holes of the fixing arrangement 40 of FIG. 4, namely, the pin holes46 formed in the flange ring 3 b and the outer race 1 can be formed bydrilling, so that these pin holes can be formed more easily than theholes of the fixing arrangement 40 of FIG. 3, because the fixingarrangement of FIG. 4 includes threaded holes.

The bearing of FIGS. 5 and 6 has the flange ring 3 b in abutment withthe end surface of the outer race 1. The fixing arrangement 40 of FIGS.5 and 6 includes a plurality of circumferentially spaced apart annulargrooves 48 each formed partially in the radially outer surface of theouter race 1 and partially in the radially outer surface of the flangering 3 b so as to bridge the abutment line between the outer race 1 andthe flange ring 3 b. The fixing arrangement 40 of FIGS. 5 and 6 furtherincludes annular fastening members 49 each fitted in a respective one ofthe annular grooves 48. The fastening members 49 may be simply fitted inthe respective annular grooves 48, or press-fitted in the annulargrooves 48. Or instead of press-fitting, the fastening members 49 may befixed in the grooves 48 by adhesive bonding. The fastening members 49may be further caulked to more reliably prevent separation.

Since the annular grooves 48 which bridge the outer race 1 and theflange ring 3 b can be formed by cutting, the fixing arrangement 40shown in FIGS. 5 and 6 can be formed more easily than the fixingarrangement 40 including the threaded holes. Also, the fixingarrangement 40 of FIGS. 5 and 6 can more strongly fix together the outerrace 1 and the flange ring 3 b.

In FIG. 7, as the fixing arrangement 40 for fixing together the outerrace 1 and the flange ring 3 b, the flange ring 3 b is brought intoabutment with the end surface of the outer race 1, and the abutmentsurfaces are welded together at the outer peripheral portions thereof,as shown by weld joint 50 in FIG. 7.

By using the fixing arrangement 40 of FIG. 7, which comprises welding,it is possible to reduce the number of parts of the bearing compared tothe bearing which uses the fixing arrangement 40 including bolts orpins. The fixing arrangement 40 of FIG. 7 is also inexpensive because itneeds neither threaded holes nor pin holes.

The fixing arrangement 40 shown in FIG. 8 includes a fitting recesscomprising a threaded hole 51 formed in the end surface of the outerrace 1, and an external thread 52 formed on the outer periphery of theflange ring 3 b. The external thread 52 is in threaded engagement withthe internal thread 51 a of the threaded hole 51 with the flange ring 3b driven into the threaded hole 51 until the flange ring 3 b abuts theclosed end surface of the threaded hole 51.

The fixing arrangement 40 shown in FIG. 9 includes a fitting recess 53formed in the end surface of the outer race 1, having a diameter largerthan the inner diameter of the outer race 1, and in which the flangering 3 b is press-fitted. When the flange ring 3 b is press-fitted, theouter race 1 could be radially outwardly deformed. To prevent suchdeformation, the outer race 1 is formed, in the end surface thereof,with an annular groove 54.

The fixing arrangement 40 of FIG. 9 can be formed more easily than thefixing arrangement 40 of FIG. 8 because the former requires no threadsas required in the latter.

In FIGS. 2 to 9, of the two inwardly extending flanges 3 a and 3 b ofthe outer race 1, only the flange 3 b comprises the flange ring 3 bseparate from the outer race 1 and fixed to the outer race 1. As shownin FIG. 10, however, both of the inwardly extending flanges 3 a and 3 bmay comprise flange rings separate from the outer race 1 and fixed tothe outer race 1. In FIG. 10, each flange ring is fixed to the outerrace by the same fixing arrangement 40 as shown in FIG. 2, which usesbolts. However, any of the fixing arrangement 40 shown in FIGS. 3 to 9may be used instead.

By using flange rings for both of the two inwardly extending flanges 3 aand 3 b as shown in FIG. 10, it is possible to simplify the shape of theouter race 1.

FIG. 11 shows a different cylindrical roller bearing embodying thepresent invention. In this embodiment, the outer race 61 has no flanges,and is formed with lead-in chamfers 63 on the respective axial ends of acylindrical raceway 62 formed on the inner periphery of the outer race61.

The inner race 71 includes outwardly extending flanges 73 a and 73 bprovided at the respective axial ends of a cylindrical raceway 72 formedon the outer periphery of the inner race 71. The flange 73 b comprises aflange ring separate from and fixed to the inner race 71.

The cylindrical rollers 21 are retained by a retainer 81 locatedradially outwardly of the pitch circle diameter PCD of the cylindricalrollers 21 so as to be guided by the raceway 62 of the outer race 61. Inparticular, the inner diameter of the retainer 81 is larger than thepitch circle diameter PCD of rollers 21. Numeral 82 in FIG. 11 indicatespockets formed in the retainer 81 in which the respective cylindricalrollers 21 are received.

Since the retainer 81 of the cylindrical roller bearing shown in FIG. 11is also not located on the pitch circle PC, it is possible to increasethe size and/or number of the cylindrical rollers 21 while maintainingsufficient strength of the retainer 81. In other words, with thisarrangement, it is possible to increase the load capacity of thecylindrical roller bearing while maintaining sufficient strength of theretainer 81.

In this arrangement, even if the outer race 61 separates from thebearing, the cylindrical rollers 21 do not separate, and the cylindricalrollers 21 and the retainer 81 remain mounted to the inner race 71. Thesubassembly of the cylindrical rollers 21, the retainer 81 and the innerrace 71 can thus be easily mounted on a shaft, and also, the cylindricalroller bearing can be easily assembled.

In FIG. 11, only the outwardly extending flange 73 b comprises theflange ring. However, the other outwardly extending flange 73 a may alsocomprise a flange ring fixed to the inner race 71.

In FIG. 11, the flange ring 73 b is fixed to the outer race by the samefixing arrangement 40 as shown in FIG. 2, which uses bolts. However, anyof the fixing arrangement 40 shown in FIGS. 3 to 9 may be used instead.

In the embodiment shown in FIG. 12, the retainer 31 is uniform inthickness over the entire axial length thereof. As shown in FIG. 12,however, the ring portions 34 may have smaller inner diameters than theinner diameters of the pillars 33 such that the ring portions 34 arelarger in wall thickness than the pillars 33.

With the arrangement in which the ring portions 34 are larger in wallthickness than the pillars 33, it is possible to keep the pillars 33 outof contact with the raceway 12 of the inner race 11. This reduces wearof the raceway 12 and also reduces resistance to rotation of thecylindrical roller bearing.

By retaining the cylindrical rollers 21 with the retainer 31 as shown inFIGS. 2 and 12, it is possible to reduce radial movements of thecylindrical rollers, which in turn eliminates the necessity for thelead-in chamfers 13.

In the embodiment shown in FIG. 2, the retainer 31 is guided by theinner race, as described above. However, the retainer 31 may be guidedby the cylindrical rollers 21 as shown in FIG. 13. By guiding theretainer 31 with the rollers, it is possible to keep the retainer 31 outof contact with the inner race 11, thus reducing wear of the raceway 11and also reducing rotational resistance and thus torque loss.

DESCRIPTION OF THE NUMERALS

-   1. Outer (bearing) race-   2. Raceway-   3 a. Inwardly extending flange-   3 b. Inwardly extending flange (flange ring)-   4. Small-diameter cylindrical surface-   5. Cylindrical portion-   11. Inner (bearing) race-   12. Raceway-   21. Cylindrical roller-   31. Retainer-   32. Pocket-   33. Pillar-   34. Ring portion-   40. Fixing means-   41. Bolt inserting hole-   42. Threaded hole-   43. Bolt-   44. Bolt inserting hole-   45. Threaded hole-   46. Pin hole-   47. Pin-   48. Annular groove-   49. Fastening member-   50. Welded portion-   53. Fitting recess-   54. Annular groove-   61. Outer (bearing) race-   62. Raceway-   71. Inner (bearing) race-   72. Raceway-   73 a. Outwardly extending flange-   73 b. Outwardly extending flange (flange ring)-   81. Retainer-   82. Pocket

1. A cylindrical roller bearing comprising an outer race formed with acylindrical raceway on an inner periphery of the outer race, an innerrace formed with a cylindrical raceway on an outer periphery of theinner race, a plurality of cylindrical rollers disposed between theinner race and the outer race, and a cylindrical retainer formed withcircumferentially spaced apart pockets which are equal in number to thecylindrical rollers and in which the respective cylindrical rollers arerotatably received, wherein the outer race is a flanged bearing racehaving a first flange configured to guide first end surfaces of therespective cylindrical rollers, and a second flange configured to guidesecond end surfaces of the respective cylindrical rollers, and whereinthe inner race is a flangeless bearing race having no flanges, whereinthe retainer includes pillars defined between the respective adjacentpairs of the pockets and contacting and keeping the cylindrical rollersspaced apart from each other, the pillars having radially outer surfaceslocated radially inwardly of a pitch circle of the cylindrical rollerssuch that the pillars are located between a pitch circle of thecylindrical rollers and the cylindrical raceway of the flangelessbearing race, wherein at least one of the first and second flangescomprises a flange ring which is a separate member from, and fixed to,the flanged bearing race, and wherein the flange ring is configured tobe fixed to the flanged bearing race after fitting the cylindricalrollers in the flanged bearing race.
 2. The cylindrical roller bearingof claim 1, wherein the flange ring fixed to the flanged bearing race bya fixing arrangement comprising an axial bolt inserting hole formed inthe flange ring, a threaded hole formed in an end surface of the flangedbearing race, and a bolt, and wherein said fixing arrangement isconfigured such that the bolt can be inserted through the bolt insertinghole, driven into the threaded hole and tightened, thereby fixing theflange ring to the flanged bearing race.
 3. The cylindrical rollerbearing of claim 1, wherein the flange ring is fixed to the flangedbearing race by a fixing arrangement comprising a small-diametercylindrical surface provided at an axial end of the flanged bearing raceand formed with a radial threaded hole, a cylindrical portion providedon the flange ring and fitted on the small-diameter cylindrical surface,said cylindrical portion being formed with a radial bolt inserting hole,and a bolt, and wherein said fixing means is configured such that thebolt can be inserted through the bolt inserting hole, driven into thethreaded hole and tightened, thereby fixing the flange ring to theflanged bearing race.
 4. The cylindrical roller bearing of claim 1,wherein the flange ring is fixed to the flanged bearing race by a fixingarrangement comprising a pin hole extending from an outer side surfaceof the flange ring through the flange ring, and into the flanged bearingrace, and a pin press-fitted in the pin hole.
 5. The cylindrical rollerbearing of claim 1, wherein the flange ring is fixed to the flangedbearing race by a fixing arrangement comprising a small-diametercylindrical surface provided at an axial end of the flanged bearingrace, a cylindrical portion provided on the flange ring and fitted onthe small-diameter cylindrical surface, a pin hole extending from aperipheral surface of the cylindrical portion through the cylindricalportion, and into the flanged bearing race, and a pin press-fitted inthe pin hole.
 6. The cylindrical roller bearing of claim 1, wherein theflange ring is fixed to the flanged bearing race by a fixing arrangementcomprising a plurality of circumferentially spaced apart annular grooveseach formed partially in a peripheral surface of the flanged bearingrace and partially in a peripheral surface of the flange ring so as tobridge the flanged bearing race and the flange ring when the flange ringis brought into abutment with an end surface of the flanged bearingrace, and annular fastening members each fitted in each of the annulargrooves.
 7. The cylindrical roller bearing of claim 1, wherein theflange ring is fixed to the flanged bearing race by a fixing arrangementcomprising a fitting recess formed in an end surface of the flangedbearing race and configured such that the flange ring can bepress-fitted in the fitting recess.
 8. The cylindrical roller bearing ofclaim 7, wherein an annular groove is formed in the end surface of theflanged bearing race.
 9. A cylindrical roller bearing comprising anouter race formed with a cylindrical raceway on an inner periphery ofthe outer race, an inner race formed with a cylindrical raceway on anouter periphery of the inner race, a plurality of cylindrical rollersdisposed between the inner race and the outer race, and a cylindricalretainer formed with circumferentially spaced apart pockets which areequal in number to the cylindrical rollers and in which the respectivecylindrical rollers are rotatably received, wherein the inner race is aflanged bearing race having a first flange configured to guide first endsurfaces of the respective cylindrical rollers, and a second flangeconfigured to guide second end surfaces of the respective cylindricalrollers, and wherein the outer race is a flangeless bearing race havingno flanges, wherein the retainer includes pillars defined between therespective adjacent pairs of the pockets and contacting and keeping thecylindrical rollers spaced apart from each other, the pillars havingradially inner surfaces located radially outwardly of a pitch circle ofthe cylindrical rollers such that the pillars are located between thepitch circle of the cylindrical rollers and the cylindrical raceway ofthe flangeless bearing race, wherein at least one of the first andsecond flanges comprises a flange ring which is a separate member from,and fixed to, the flanged bearing race, and wherein the flange ring isconfigured to be fixed to the flanged bearing race after fitting thecylindrical rollers in the flanged bearing race.
 10. The cylindricalroller bearing of claim 9, wherein the flange ring fixed to the flangedbearing race by a fixing arrangement comprising an axial bolt insertinghole formed in the flange ring, a threaded hole formed in an end surfaceof the flanged bearing race, and a bolt, and wherein said fixingarrangement is configured such that the bolt can be inserted through thebolt inserting hole, driven into the threaded hole and tightened,thereby fixing the flange ring to the flanged bearing race.
 11. Thecylindrical roller bearing of claim 9, wherein the flange ring is fixedto the flanged bearing race by a fixing arrangement comprising asmall-diameter cylindrical surface provided at an axial end of theflanged bearing race and formed with a radial threaded hole, acylindrical portion provided on the flange ring and fitted on thesmall-diameter cylindrical surface, said cylindrical portion beingformed with a radial bolt inserting hole, and a bolt, and wherein saidfixing means is configured such that the bolt can be inserted throughthe bolt inserting hole, driven into the threaded hole and tightened,thereby fixing the flange ring to the flanged bearing race.
 12. Thecylindrical roller bearing of claim 9, wherein the flange ring is fixedto the flanged bearing race by a fixing arrangement comprising a pinhole extending from an outer side surface of the flange ring through theflange ring, and into the flanged bearing race, and a pin press-fittedin the pin hole.
 13. The cylindrical roller bearing of claim 9, whereinthe flange ring is fixed to the flanged bearing race by a fixingarrangement comprising a small-diameter cylindrical surface provided atan axial end of the flanged bearing race, a cylindrical portion providedon the flange ring and fitted on the small-diameter cylindrical surface,a pin hole extending from a peripheral surface of the cylindricalportion through the cylindrical portion, and into the flanged bearingrace, and a pin press-fitted in the pin hole.
 14. The cylindrical rollerbearing of claim 9, wherein the flange ring is fixed to the flangedbearing race by a fixing arrangement comprising a plurality ofcircumferentially spaced apart annular grooves each formed partially ina peripheral surface of the flanged bearing race and partially in aperipheral surface of the flange ring so as to bridge the flangedbearing race and the flange ring when the flange ring is brought intoabutment with an end surface of the flanged bearing race, and annularfastening members each fitted in each of the annular grooves.
 15. Thecylindrical roller bearing of claim 9, wherein the flange ring is fixedto the flanged bearing race by a fixing arrangement comprising a fittingrecess formed in an end surface of the flanged bearing race andconfigured such that the flange ring can be press-fitted in the fittingrecess.
 16. The cylindrical roller bearing of claim 15, wherein anannular groove is formed in the end surface of the flanged bearing race.